ST72682 STMicroelectronics, ST72682 Datasheet - Page 23

• Manufacturer Part Number: ST72682
• Description: USB 2.0 high-speed Flash drive controller
• Manufacturer: STMicroelectronics

ST72682
7.6
7.6.1
EMC characteristics
Susceptibility tests are performed on a sample basis during product characterization.
Functional EMS (Electromagnetic Susceptibility)
Based on a simple running application on the product (toggling 2 LEDs through I/O ports),
the product is stressed by two electromagnetic events until a failure occurs (indicated by the
LEDs).
A device reset allows normal operations to be resumed. The test results are given in the
table below based on the EMS levels and classes defined in application note AN1709.
Designing hardened software to avoid noise problems
EMC characterization and optimization are performed at component level with a typical
application environment and simplified MCU software. It should be noted that good EMC
performance is highly dependent on the user application and the software in particular.
Therefore it is recommended that the user applies EMC software optimization and
prequalification tests in relation with the EMC level requested for his application.
Table 16.
Symbol
V
V
FESD
FFTB
ESD: Electrostatic Discharge (positive and negative) is applied on all pins of the device
until a functional disturbance occurs. This test conforms with the IEC 1000-4-2
standard.
FTB: A Burst of Fast Transient voltage (positive and negative) is applied to V
V
conforms with the IEC 1000-4-4 standard.
Software recommendations
The software flowchart must include the management of runaway conditions such as:
–
–
–
Prequalification trials
Most of the common failures (unexpected reset and program counter corruption) can
be reproduced by manually forcing a low state on the RESET pin or the Oscillator pins
for 1 second.
To complete these trials, ESD stress can be applied directly on the device, over the
range of specification values. When unexpected behavior is detected, the software can
be hardened to prevent unrecoverable errors occurring (see application note AN1015).
SS33
Corrupted program counter
Unexpected reset
Critical Data corruption (control registers...)
Voltage limits to be applied
on any I/O pin to induce a
functional disturbance
Fast transient voltage burst
limits to be applied through
100pF on V
pins to induce a functional
disturbance
through a 100pF capacitor, until a functional disturbance occurs. This test
EMS characteristics
Parameter
DD33
and V
SS33
V
compliant with IEC 1000-4-2
V
compliant with IEC 1000-4-4
DD33
DD33
=3.3 V, T
=3.3 V, T
A
A
=+25 °C, f
=+25 °C, f
Conditions
OSC
OSC
=12 MHz
=12 MHz
Electrical characteristics
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Level/Class
DD33
4B
4A
and
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